Malicious PDF — malware analysis report

Static analysis result for SHA-256 800cb9232ea8d442…

MALICIOUS

PDF

31.7 KB Created: 2020-04-20 17:31:35 +03:00 Authoring application: wkhtmltopdf 0.12.1.4 (via Qt 4.8.6)
MD5: 0da17ac7c4e567203aeffa42faeb7285 SHA-1: 38b1a77f8767098914bcd9a18cfb2fb97c51b0ca SHA-256: 800cb9232ea8d442e14835dfea9bc0f728d95aebb41ecb360db179eaa6dbd62a
94 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious Link

The PDF file contains a large number of external links, many of which are hosted on newly created domains and point to PDF files. This behavior is indicative of a link farm or SEO poisoning attack, designed to drive traffic to malicious sites. The ML classifier also strongly flagged this PDF as malicious. The document body, though heavily obfuscated, contains text related to English tests and includes several of the extracted URLs, reinforcing the lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9994

Heuristics 4

  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://baylandesign.net/uploads/1/3/0/2/130287462/130287462.html#english+tests+advanced+level+with+answers
    • http://howellbridgefinancing.com/uploads/1/3/0/5/130550931/fd8292a1bc1ffd.pdf
    • http://riderfly.com/uploads/1/3/1/3/131398269/movumozopizivabem.pdf
    • http://theatrebrum.com/uploads/1/3/1/4/131408899/18865.pdf
    • http://vrchotalifestyle.com/uploads/1/3/0/5/130547846/5939050.pdf
    • http://sjwirkkala.com/uploads/1/3/0/5/130590548/e80b977980bb4.pdf
    • http://coloradobankingcareers.com/uploads/1/3/0/5/130538875/jitupopaxixu-guzedakebelutef-ketafepibu-mozujinud.pdf
    • http://adstorank.com/uploads/1/3/0/7/130775014/7509264.pdf
    • http://myriadproduceconsultingserv.com/uploads/1/3/0/2/130289745/758711.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000054a4.bin
9bcc71dd7586cc6c8fca676875178fcc8b336cbfa65b79eb6e5fa936deaae8a1		 pdf-font-stream PDF embedded font (sfnt) at offset 0x54A4 7804 bytes

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